The present invention relates to a transparent plate comprising, on at least one of its faces, a plurality of geometric features in relief relative to a general plane of said face. The invention also relates to an assembly comprising such a transparent plate and an element capable of collecting or emitting radiation. Furthermore, the invention relates to a method of manufacturing such a transparent plate.
An element capable of collecting radiation is, in particular, an element able to collect and convert the energy originating from a radiation into electrical energy, such as a photovoltaic cell. An element capable of emitting radiation is, in particular, an element able to convert electrical energy into radiation, such as an OLED (Organic Light Emitting Diode).
Conventionally, a photovoltaic module or an OLED device comprises, as a front substrate (or substrate having a glass function), a transparent plate which mechanically protects the energy conversion elements, namely the photovoltaic cells or the OLED structures, whilst allowing a good transmission of radiation toward or from these energy conversion elements. This transparent plate may, in particular, be made of a transparent glass, preferably clear or extra-clear glass, having a very low content of iron oxides, such as the glass “DIAMANT” or the glass “ALBARINO” marketed by Saint-Gobain Glass.
One way of increasing the energy conversion efficiency of a photovoltaic module or an OLED device is to improve the transmission properties of the plate forming the front substrate, by limiting the reflection of the radiation incident on the plate, coming either from the air in the case of a photovoltaic module, or from the inside of the device in the case of an OLED device. To this end, it is known to texture at least the face of the plate directed away from the energy conversion elements, by providing it with a plurality of concave or convex geometric features in relief with respect to a general plane of this face. Within the meaning of the invention, the general plane of a textured face is the plane containing the points of this face which do not form part of the features or, in the case of contiguous features, the points at the junctions between the features. The features may, in particular, be pyramids or cones, or features that have a favored longitudinal direction, such as grooves or ribs. However, the increase in efficiency due to the use of prior art textured plates as front substrates of energy conversion devices remains limited. This is because conventional texturing techniques, in particular by rolling, as described in patent applications WO-A-03/046617, WO-A-2005/111670 and WO-A-2007/015019, do not at the present time allow features having a perfect geometry to be formed.